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I have an idea to optimize any refrigerator that gets power from an intermittent source like solar or wind.
I’ll make a simple electronic controller that switches between two modes:

When there is input power (such as when the solar panels are working, wind turbine is spinning, etc.), the controller sets the thermostat to a rather cold setting.

When there is no input power (sun is not out, or no wind for wind turbine, etc.), the controller sets the thermostat to a setting that is not so cold.

The idea behind this strategy is to make good use of power when it’s available, and to conserve energy when power is not available. By getting the contents of the refrigerator quite cold during the day, it will take them longer to warm up at night… and at night, with that higher thermostat setting, we’ll only turn on the compressor once in a while.

To further help things – and this works in any fridge or freezer – you can keep a couple of bottles of water in the fridge or some big frozen things in the freezer, to function as a ‘thermal flywheel,’ just like putting a “cool pack” or bag of ice into a cooler.

I’m curious to see just how long a controller like this will let the fridge can go before having to turn on the compressor. It would be great if it could run just during the day when there’s solar power available. We’ll find out!